Cooling system for groove closing tapes of continuous ingot casting wheel machines

ABSTRACT

This disclosure relates to a cooling system for cooling the groove closing tape or belt of a continuous ingot casting wheel machine comprising a plurality of nozzles directed against the operating portion of said tape and providing a plurality of cooling liquid jets impinging against said portion of the tape.

United States Patent Inventor Ilario Properzl c/o (0ntinuus-\ ia Cosimo del Fame. 10. Milan, Italy Appl. No 728,864 Filed May I3, 1968 Patented June 8, 1971 Priority Nov. 10, 1967 Italy 22,572 A/67 COOLING SYSTEM FOR GROOVE CLOSING TAPES OF CONTINUOUS INGOT CASTING WHEEL MACHINES 2 Claims, 5 Drawing Figs.

US. Cl

164/87 Int. Cl B22d 11/06, B22d 11/12 Field of Search 164/87,

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[56] References Cited UNITED STATES PATENTS 3,354,937 11/1967 Jackson, Jr 164/87 3,429,363 2/1969 I-Iazelett et al 164/283X FOREIGN PATENTS 626,031 4/1963 Belgium 164/278 527,337 5/1955 Italy 164/276 Primary Examiner-J. Spencer Overholser Assistant Examiner-R. Spencer Annear Att0rneys-Guido Modiano and Albert 10511 ABSTRACT: This disclosure relates to a cooling system for cooling the groove closing tape or belt of a continuous ingot casting wheel machine comprising a plurality of nozzles directed against the operating portion of said tape and providing a plurality of cooling liquid jets impinging against said portion of the tape.

' III/III PATENTEU JUN 8 l97| SHEET 1 [IF 5 INVENTOR. llario ro pg gen 4' PATENTED JUN 8197! SHEET Q 0F 5 INVENTOR. llarlo Propzrzi BY PATENTED JUN 8 I971 SHEET 5 [1F 5 INVENTOR.

\lario Pmpeni BY COOLING SYSTEM FOR GROOVE CLOSING TAPES OF CONTINUOUS INGO'I' CASTING WHEEL MACHINES CROSS-REFERENCES TO RELATED APPLICATIONS Certain structural parts of the continuous casting wheel machine described in this application are similar to those described in my copending application Ser. No. 696,312 filed Jan. 8, 1968, now US. Pat. No. 3,529,658.

BACKGROUND OF THE INVENTION The present invention relates to a cooling system providing jets of a cooling liquid acting on the outside of a groove closing metal tape or casting belt for use in a continuous casting machine.

As it is known, a continuous casting machine having a casting wheel mounted for rotation therein to produce continuous metal bars essentially comprises a radially opened groove in the peripheral portion of said casting wheel. This groove is covered along a certain portion of arc by a metal tape which closes said groove and moves therewith along said portion of arc to retain therein a metal in liquid or molten state, which is cast into the groove at the beginning of the portion thereof covered by the said tape, A metal ingot in the form of a continuous solid bar is drawn from the point of thegroove, where said tape leaves the periphery of the wheel.

In order that the bar be well formed and evenly solidified at the drawing point, a controlled cooling is required along that portion of the forming ingot which is covered by said tape and placed in the corresponding portion of said groove.

The high output requirements in a modern machine make-it necessary to use tapes of increasingly reduced thickness in order to obtain a rapid dispersion of heat; Due to production requirements, in fact, when dealing with ingots of small cross section, the casting wheel has to complete an angular displacement corresponding to its portion covered by the tape in a time period of the order of seconds, per example, whence the dispersion or loss of heat or cooling must take place with extreme rapidity.

This rapid cooling is usually carried out by means of water jets on both the inside surfaces of the casting wheel and the outer surface of the tape.

The cooling of the tape is of particular importance owing also to the flexibility requirements, small thickness and fatigue stresses to which such tape is subjected.

Cooling of the tape is hindered due to the formation of a plurality of spots on the outer surface of the tape which are covered by a heat insulating steam layer, when the water flowing over the surface to be cooled is not capable to removesuch layer.

In the known cooling systems, the jets of cooling liquid are directed in the longitudinal direction of the tape and the jets are distributed in succession over the operative arc of the tape. In this way the steam layer which is formed is not removed from the tape and a part thereof is only shifted along the arc of the tape. In addition the jets intersect each other thereby reducing the cooling efficiency of the jets.

The steam bubbles created cause a defective ingot structure, the ingot being subjected to crystalization malformations, segregations, cracks, surface roughness, brittleness etc.

and these defects become more noticeable in increased ingot section. This is an important problem also in view of the fact that a trend exists nowadays of increasing ingot sections from cm to 30cm and more, such sections requiring a tape width of 70 mm. and even more.

SUMMARY OF THE INVENTION In order to meet the above severe requirements an object of the present invention is to provide a cooling system which prevents steam layers from being formed on the outer surface of the tape.

Another object of the present invention is to provide a colling system which makes it possible to use a very thin tape 1mm. or even thinner) consisting of low-carbon steel.

Another object of this invention is to provide a cooling system of reliable operation and rational structure, capable of creating an extremely rapid but regular cooling liquid flow over the tape, approaching as far as possible laminar conditions of flow.

Another object of this invention is to provide a cooling system easy to manufacture, of low cost and adapted tobe operated also in continuous casting machines already existing and available on the market.

These and still other objects which will be better apparent below are attained by a cooling system according to the invention for the groove closing tape of a continuous ingot casting wheel machine including a plurality of cooling liquid jet creating nozzles directing the jets against said closing tape, and duct means for conveying the cooling liquid under pressure to the nozzles, wherein the improvement comprises a plurality of cooling liquid jet creating nozzle means directed towards said tape and transverse to the longitudinal direction thereof.

BRIEF DESCRIPTION OF THE DRAWING Further features and advantages of the invention will appear more clearly from the following detailed description with reference to the accompanying drawings, in which:

FIG. 1 diagrammatically shows in a side view a' continuous casting machine, where a cooling systemaccording to the invention may be used,

FIG. 2 is a verticaldiametral cross section of the casting wheel in the machine'of'FIG. I, I

FIG. 3 shows a detail, in an enlarged scale, of the lower part of FIG. 2, in vertical cross section,

FIG. 4 shows the patternof water jets'impinging on a tape, the view being taken according to line C-D of FIG. 3,

FIG. 5 shows the pattern of water jets provided only at one side of the tape.

DESCRIPTION, OF THE FREF ERRED EMBODIMENT FIG. 1 shows in elevational view' a continuous casting machine having a casting wheel I mounted for rotation therein. A' peripheral groove 2in said casting wheel 1 is fed with molten or liquidmetal through the nozzle 3 extending from a feeding crucible 4, which is in turn fed by conventional known means (not shown).

The groove 2 is cooled internally by a series of water jets 5.

A covering tape or belt 7 closes the'groove' 2 from the point in which it is controlled by' the roller 8 to the point '9 in which the solid ingot 10 leaves the wheel 2.

The tape 7 is maintained under constanttension by means of devices (not shown) which act onthe pulley 11;

A device 12 allows the lower point of the nonle'3 to be adjusted below the filling level 13 by feeding means known in the art.

FIG. 2 shows a vertical diametral cross section of the casting wheel comprising a rotation shaftl4 carrying "a disc member 15. On the periphery of member Sis secured a grooved ring 2 which is cooled internally by jets 16 carried on an annular manifold 17 which is in turn fed via tubes'l8 and 19 by a tube 20 connected to a source of water under pressure (not shown). In the'lower part of FIG. 2 the groove 2 is shown containing an ingot 21 whilebeing formed and closed by the tape 7 series of inclined jets 23 and 24, which transversely impinge on the tape 7, alternately in opposite directions so as to avoid intersection of jets. As clearly visible from'FIG. 3 the nozzles 23 and 24 creating the jets 23a and 2% have elongated or slit like orifices 23b and 24b respectively. It will be noted from FIG. 3 that the length of the slits 23b and 24b extends in a plane perpendicular to the tape 7. In this way the jets have a bladelike shape of small thickness and great width, the

thickness being intended as the dimension of the jet in the direction parallel to the longitudinal direction of the tape 7, and the width being intended as the dimension of the jet extending in a plane transverse or perpendicular to the tape 7.

The cooling liquid directly impinges at high velocity the central hot zone of tape 7 from A to B, while the liquid heated by contact leaves immediately the tape since the jets are directed transversely to the tape and are offset in their transversal arrangement, i.e. not opposite to one another, thus avoiding mutual interference. With the expression direct impingement" it is meant that at least one substantial portion of the liquid coolant particles reaches the entire central zone from A to B, i.e. the zone opposite the molten metal containing mould, directly from the nozzles 23 or 24, i.e. without flowing first over the tape 7.

FIG. 4 is a cross section view taken along line C-D of manifold 22 in FIG. 3. In this FIGURE the two series of oppositely directed but offset jets 23 and 24 may be seen, which after impinging the tape at the hot zone A and B freely escape towards sides 25 and 26 in such manner as to prevent hot water from mixing with cool water and so as to remove from the tape surface all little steam bubbles, which could be formed in possible turbulence zones therein.

FIG. shows a view similar to that of FIG. 4 but with jets arranged only at one side of the tape.

From the foregoing it will be understood that the cooling efficicncy and also the quantity of fresh cooling liquid per surface and time units are highly increased, the hot liquid being immediately expelled from the tape.

Various changes and modifications may be made within the scope defined by the following claims.

lclaim:

l. A cooling system for the casting belt of a continuous metal casting machine of the casting wheel-type, wherein the casting wheel has a groove along its periphery and a moving mold is provided between said grooved periphery and the casting belt portion closing said groove and wherein said casting belt has an effective width corresponding to the width of said mold defining groove, said periphery of the casting wheel rotating in a plane perpendicular to the axis of rotation of the casting wheel, the cooling system including a plurality of cooling liquid jet creating nozzles distributed along said casting belt portion and having a nozzle axis directed against said casting belt and transverse to said plane, wherein according to the improvement said nozzles have each an orifice elongated in a direction perpendicular to said nozzle axis and lying in a plane transverse to said casting belt, the dimension of said elongated orifice in said direction having such a size that the cooling liquid jet ejected from said nozzle impinges directly against said belt portion over an area having a widthways extension with respect to said belt at least as great as said effective width of said casting belt, to produce uniform cooling across said casting belt portion.

2. A cooling system according to claim Lwherein said nozzles are arranged along each side of said casting belt, each nozzle on one side of the belt being offset with respect to a nozzle on the other side of the belt, and directed in opposite directions. 

1. A cooling system for the casting belt of a continuous metal casting machine of the casting wheel-type, wherein the casting wheel has a groove along its periphery and a moving mold is provided between said grooved periphery and the casting belt portion closing said groove and wherein said casting belt has an effective width corresponding to the width of said mold defining groove, said periphery of the casting wheel rotating in a plane perpendicular to the axis of rotation of the casting wheel, the cooling system including a plurality of cooling liquid jet creating nozzles distributed along said casting belt portion and having a nozzle axis directed against said casting belt and transverse to said plane, wherein according to the improvement said nozzles have each an orifice elongated in a direction perpendicular to said nozzle axis and lying in a plane transverse to said casting belt, the dimension of said elongated orifice in said direction having such a size that the cooling liquid jet ejected from said nozzle impinges directly against said belt portion over an area having a widthways extension with respect to said belt at least as great as said effective width of said casting belt, to produce uniform cooling across said casting belt portion.
 2. A cooling system according to claim 1, wherein said nozzles are arranged along each side of said casting belt, each nozzle on one side of the belt being offset with respect to a nozzle on the other side of the belt, and directed in opposite directions. 